#!/bin/bash
hour=$(date +%H)
echo "$hour"
if((hour<=12))
 then
  echo "good morning,$USER!"
elif((hour>12 && hour <=18))
 then
   echo "good afternoon,$USER!"
else 
   echo "good night,$USER!"
fi
echo "当前时间是：$(date +"%Y-%m-%d %H:%M:%S")"

